Numerous massage machines have been developed for massaging the human body in an attempt to stimulate circulation, tone up the muscles and to improve the general health of the user when the machine rolls against the body, oscillates rotationally or simply vibrates. Certain types of existing devices have massage applicators which are supported by, or embedded into, a structure, such as a chair, table or back cushion. In these types of devices, the applicators are driven by an electric motor which eliminates the need for manual assistance in the massaging process. However, the movement patterns and ranges for the applicators are limited and usually confined to specific areas of the body and, therefore, are not suitable for massaging an entire region of the body.
Hand-held massagers, also in general use, can be applied to any area of the body, but are difficult to use and tedious. Effective massaging with hand-held devices requires repetitious manual movement of the applicator for extended periods of time. Furthermore, certain areas of the body cannot easily be reached by a person applying the applicator for self-massage. To obtain an effective massage to cover all areas of the body, a second individual is required.
Devices for specifically massaging the back and spinal area have included machines wherein the entire massaging apparatus is deposed beneath a body supporting table surface such that massage wheels or other pressure exerting components may apply pressure upwardly, through the table surface, so as to massage the spinal area of a human subject lying in a generally supine position on a table surface. Other devices for specifically massaging the back and spinal area have included machines wherein the entire massaging apparatus is disposed above a body supporting surface such that massage wheels or other pressure exerting components may apply pressure downwardly to massage the spinal area of a human subject lying in a generally prone position on a table surface.
Devices which apply pressure downwardly to a portion of the human body which is positioned on a table surface include safety features which limit the amount of pressure that can be applied downwardly to prevent the device from applying excessive compressive pressure and injuring the body portion. Such devices typically include a force or pressure sensing switch which is actuated when a preset force or pressure is exceeded. Such devices are problematic in that in the event of a switch or other electrical failure, the safety feature is rendered inoperative. Such a failure could occur during use of the device and, therefore, may result in injury to the human body lying on the support surface. Hence there is a need for such a massaging device which can limit the maximum pressure applied to the human body which does not rely upon an external power source.
Moreover, massaging devices are also problematic because they typically only sense the applied force along a single axis, usually a vertical axis. Such massaging devices use the sensed force as feedback to control the amount of force applied to the body portion in accordance with a predetermined force selected by the user. However, typical massaging devices apply forces horizontally because the applicator moves horizontally across the human body which is not planar. For instance, as an applicator moves upwardly and horizontally over and in engagement with an inclined portion of the body, horizontal forces are applied due to friction and the inclination of the body. Conventional massaging devices do not include any means for sensing the forces applied horizontally against the human body and, therefore, the applicator is not accurately controlled to provide the selected predetermined force.
The present invention is directed to a sensor device in a system for massaging a portion of the human body which is positioned on a supporting surface by applying a compressive pressure downwardly toward the supporting surface. The system of the present invention uses a control signal from the sensor device to mechanically limit the maximum amount of pressure applied to the human body. Using the present invention the forces applied to the human body along both vertical and horizontal axes are sensed and controlled to accurately apply the selected massaging forces. Hence, the present invention provides a safer and more accurate massage of the human body.